Aluminium High
Pressure Diecasting

Casting capability across six machines with locking forces from 125 to 900 tonne enables Kemlows to produce aluminium parts up to 12 kg shot weight.

Zinc High Pressure Diecasting

Casting capability across six machines with locking forces from 25 to 125 tonne enables Kemlows to produce zinc parts up to 4 kg shot weight.

CNC
Machining

Dedicated on-site state of the art CNC machining facility.

LM2 Castings

LM2

Aluminium Casting Alloy (AL – Si10Cu2Fe)

Colour Code – Red / White

Chemical
composition

Copper 0.7
– 2.5

Magnesium
0.3 Max

Silicon
9.0 – 11.5

Iron
1.0 Max

Manganese
0.5 Max

Nickel
0.5 Max

Zinc
2.0 Max

Lead
0.3 Max

Tin
0.2 Max

Titanium
0.2 Max

Aluminium
Remainder

Mechanical
Properties

Chill Cast

Die Cast

0.2 % Proof Stress (
N/mm2)*

90 -130

130

Tensile Stress ( N/mm2)*

150 -200

300

Elongation ( % )*

1 – 3

1 – 3

Impact Resistance. Charpy (Nm)

-

2.9

Brinell Hardness Number

65 -90

65 -90

Modulus of Elasticity (x103 N/mm2)

71

71

The values shown are typical for chill cast bars produced to the
requirements of BS 1490 or diecast 6mm diameter test bars; minimum
specification requirements are in heavy type. Charpy test is for an un-notched
test bar.

Strength at Elevated
Temperatures

The reduction in strength of the alloy at elevated temperature depends upon
composition. If the amounts of the elements present, particularly copper,
nickel and manganese are low, the strength is greatly reduced at temperatures
of the order of 250°C but if the maximum permissible amounts of these elements
are present the alloy retains moderate strength at this temperature.

It should be noted however, that other factors may restrict the use of
diecastings at elevated temperatures.

Figure for conductivity applies to Die castings. Values are approximate and
will vary with condition.

Machinability

This alloy is a little difficult to machine since the high silicon content
causes rapid tool wear. It is, however, far easier than the LM6 and LM20 alloys
as the tendency to drag is practically eliminated by the presence of copper and
other elements.

Carbide-tipped tools are advocated but high speed steel tools give good
results. A cutting lubricant and coolant should be employed.

Corrosion
Resistance

Resistance to corrosion by ordinary atmospheric conditions is good and by
marine atmosphere fairly good. It is inferior in this respect to LM6 but cab be
improved by anodic treatment.

Anodising

LM2 can be anodically treated to give a protective surface of a darkish grey
colour to the surfaces of diecastings. However, they are not generally suitable
for decorative anodising.

Casting
Characteristics

FLUIDITY – Can be cast into thin and intricate sections with ease.

PRESSURE TIGHTNESS – Suitable for leak-tight castings.

HOT-TEARING – Castings exhibit virtual freedom from hot-tearing.

TYPICAL POURING TEMPERATURE – Pouring temperatures for diecastings depend
very largely on the particular casting and the machine, and vary too widely for
a typical temperature to provide useful guidance. The melt should not, however,
be allowed to stand at temperatures only little above the freezing range or the
bottom of the melt may become enriched in such elements as iron and
manganese.

Heat
Treatment

Castings in this alloy are not heat-treated.

Applications and General
Notes

Essentially a diecasting alloy, LM2 is not normally used for other types of
casting. As a general purpose alloy its applications are extremely varied and
widespread and it may be used for almost any component which can be diecast,
unless the service conditions demand a higher resistance to corrosion or
slightly greater ductility, in which case LM6 or LM20 maybe preferred.

For the vast majority of diecastings, the alloys LM2 and LM24 are
equally suitable.